ISTANBUL (AP) — A suicide attack at Istanbul's busy Ataturk Airport Tuesday killed dozens and wounded more than 140 as Turkish officials blamed the carnage at the international terminal on three suspected Islamic State group militants.

Hundreds of frightened passengers streamed out of the airport, fleeing the latest of several bombings to strike Turkey in recent months. The attacks have increased in scale and frequency, scaring off tourists and hurting the Turkish economy, which relies heavily on tourism.

Turkish Prime Minister Binali Yildirim said 36 were dead as well as the three suicide bombers. Justice Minister Bekir Bozdag said 147 were wounded. Another senior government official told The Associated Press the death toll could climb much higher.

The senior official, who spoke on condition of anonymity in line with government protocol, at first said close to 50 people had already died, but later said that the figure was expected to rise to close to 50.

Yildirim said three suicide bombers were responsible for the attack and all initial indications suggest the Islamic State group was behind it.

"The findings of our security forces point at the Daesh organization as the perpetrators of this terror attack," Yildirim told reporters at the airport, using the Arabic name for IS. "Even though the indications suggest Daesh, our investigations are continuing."

Yildirim said the attackers arrived at the airport in a taxi and blew themselves up after opening fire. Asked whether a fourth attacker might have escaped, he said authorities have no such assessment but are considering every possibility.

The victims included some foreigners, he said, adding that many of the wounded have minor injuries but others are more badly hurt.

Another Turkish official said two of the attackers detonated explosives at the entrance of the international arrivals terminal after police fired at them, while the third blew himself up in the parking lot.

The official, who also spoke on condition of anonymity in line with government regulations and cited interior ministry information, said none of the attackers managed to get past security checks at the terminal's entrance.

Turkish airports have security checks at both the entrance of terminal buildings and then later before entry to departure gates.

Roads around the airport were sealed off for regular traffic after the attack and several ambulances could be seen driving back and forth. Passengers were left sitting on the grass outside the airport.

Hevin Zini, 12, had just arrived from Duesseldorf, Germany, with her family and was in tears from the shock.

"There was blood on the ground," she told The Associated Press. "Everything was blown up to bits... if we had arrived two minutes earlier, it could have been us."

South African Judy Favish, who spent two days in Istanbul as a layover on her way home from Dublin, had just checked in when she heard an explosion followed by gunfire and a loud bang.

She says she hid under the counter for some time.

Favish says passengers were ushered to a cafeteria at the basement level where they were kept for more than an hour before being allowed outside.

Two South African tourists, Paul and Susie Roos from Cape Town, were at the airport and due to fly home at the time of the explosions.

"We came up from the arrivals to the departures, up the escalator when we heard these shots going off," Paul Roos said. "There was this guy going roaming around, he was dressed in black and he had a hand gun."

Yildirim said air traffic at the airport, which was suspended after the attack, had resumed to normal.

The prime minister called for national unity and "global cooperation" in combatting terrorism.

"This (attack) has shown once again that terrorism is a global threat," Yildirim said. "This is a heinous planned attack that targeted innocent people."

He suggested that the attack was linked to what he said was Turkey's success against Kurdish rebels as well as steps Ankara took on Monday toward mending strained ties with Israel and Russia.

"It is meaningful that this heinous attack came at a time when we have become successful in the fight against separatist terrorism ... and at a time when we started a process of normalizing ties with our neighbors," Yildirim said.

Yildirim insisted there was no security lapse at the airport but said the fact that the attackers were carrying weapons "increased the severity" of the attack.

The private DHA news agency said the wounded, among them police officers, were transferred to Bakirkoy State Hospital.

The series of recent attacks in Turkey have been linked to Kurdish or Islamic State group militants, including two in Istanbul targeting tourists that authorities have blamed on IS.

Istanbul's Ataturk Airport was the 11th busiest airport in the world last year, with 61.8 million passengers, according to Airports Council International. It is also one of the fastest-growing airports in the world, seeing 9.2 percent more passengers last year than in 2014.

The largest carrier at the airport is Turkish Airlines, which operates a major hub there. Low-cost Turkish carrier Onur Air is the second-largest airline there.